Caves of the Ledge
This is an EarthCache and as such there is no container to find. An EarthCache is simply a place to go and learn about the world we live in. You will be asked to email me the answer to a few questions in order to log this as a find. To log this cache you will need a GPS and a flashlight.
Ledge Park, covers 83 acres along the Niagara Escarpment providing excellent views of the Horicon Marsh and the surrounding countryside. The Park has over 2 miles of well groomed hiking trails ( http://www.dodgeparks.com/pdf/Map-Ledge.pdf ) which pass through the bluffs, woods and prairie areas. The park is open from 8am to 8:30pm. Dogs must be leashed at all times. Park entry is free.
For this EarthCache you will walk a trail through Niagara Escarpment exposures. Be prepared: wear good hiking shoes and pack typical supplies such as bug spray and a first aid kit. Due to the steep nature of bluffs please take special care if you bring children to the park. The Ledge Rocks trails and the Ledge Overlook Trails do have 30-50 foot drop-offs and are NOT recommended for small children. The Upper Woods and Lower Woods trails are much more family friendly. At no time will you be required to leave the trail.
A cave or cavern is a natural underground void large enough for a human to enter or extending from the Earth’s surface far enough to be in constant darkness. There are three basic ways in which caves are formed: (1) caves formed by pressure or flow, (2) caves carved by erosion, and (3) caves dissolved by solution. The caves dissolved by solution (normally seen in limestone or Dolostone formations) are the most common caves.
The National Speleological Society of America states that there are more than 11,000 caves in the United States, and it appears likely that 100,000 caves exist in the world. While this location does have legitimate caves according to the definition above, it is doubtful that these caves would be included among that worldwide number.
You are standing on the Niagara Escarpment which is made of limestone / Dolostone. It is very likely that the caves here were formed at least in part by the second and third type of cave formation above: “carved by erosion” and “dissolved by solution”. The process of cave formation by solution begins when rainwater absorbs carbon dioxide (CO2) as it falls through the atmosphere. As the water absorbs carbon dioxide it becomes acidic. As the slightly acidic rainwater comes through the soil it absorbs even more carbon dioxide from dead plant life. The addition of the CO2 changes the ground water into a weak form of carbonic acid (H2O + CO2 = H2CO3). As the weak acid seeps into the ground it eventually contacts solid rock. If the rock is limestone or dolomite caves can form as the slightly acidic water chemically reacts to the limestone as it is flows into the Earth. As the water continues to react chemically with the limestone a larger and larger space will form.
Much of the escarpment is made of limestone also known as calcium carbonate (CaCO3) which was laid down when an ancient sea covered Wisconsin. The limestone here was laid down as a limy ooze made up of shell and shell fragments consisting of corals, brachiopods, crinoids and other types of early life. Many marine organisms extract calcium carbonate from the seawater to make shells or bones and when these organisms die their shells and bones accumulate on the seafloor. Over millions of years these sediments hardened into what we see today as the bluffs of the Ledge.
* To claim this EarthCache *
E-Mail me the answers to the following questions:
(DO NOT POST IN YOUR LOG).
Park at N43 27.908 W88 35.079 (Ledge Rock hiking trail).
Hike to N43 27.937 W88 35.101.
Here you will find a small cave at the base of the escarpment.
#1. E-mail me: How deep is this cave.
2. E-mail me: What forms of erosion do you think are at work at the cave?
#3. E-mail me: Do you think the presence of grass and other plant life above the cave affects the caves development? Why or why not?